Mechanical ladle mechanism having four-bar configuration

ABSTRACT

A mechanical ladle mechanism having a four-bar configuration. The four-bar ladle mechanism has a first bar having a first end and a second end opposite the first end, a second bar in spaced apart relationship to the first bar also having a first end and a second end opposite its first end, a third fixed bar having a first end and a second end opposite its first end, and a fourth bar in spaced apart relationship to the fixed third bar also having a first end and a second end opposite its first end. The first end of the first bar is pivotally attached to the second end of the third bar, the first end of the second bar is pivotally attached to the first end of the third bar, the first end of the fourth bar is pivotally attached to the second end of the second bar, and the second end of the fourth bar is pivotally attached to the second end of the first bar. A ladle is removably attached to the fourth bar, the longitudinal axis of the ladle being substantially parallel to the longitudinal axis of the fourth bar. A hydraulic cylinder or rack and pinion may be operatively associated with the first bar to cause it to rotate about the pivotal mounting at its first end. The second bar and fourth bar with the ladle attached follow the rotational motion of the first or driver bar.

United States Patent [191 McCarthy [111 3,774,815 Nov. 27, 1973MECHANICAL LADLE MECHANISM HAVING FOUR-BAR CONFIGURATION [76] Inventor:John McCarthy, 4133 Scottdale Rd., St. Joseph, Mich. 49085 22 Filed:Oct.30, 1972 21 Appl.No.:302,350

Primary Examiner-Robert B. Reeves Assistant Examiner-David A. ScherbelAtt0rneylrving M. Weiner et al.

[57] ABSTRACT A mechanical ladle mechanism having a four-barconfiguration. The four-bar ladle mechanism has a first bar having afirst end and a second end opposite the first end, a second bar inspaced apart relationship to the first bar also having a first end and asecond end opposite its first end, a third fixed bar having a first endand a second end opposite its first end, and a fourth bar in spacedapart relationship to the fixed third bar also having a first end and asecond end opposite its first end. The first end of the first bar ispivotally attached to the second end of the third bar,'the first end ofthe second bar is pivotally attached to the first end of the third bar,the first end of the fourth bar is pivotally attached to the second endof the second bar, and the second end of the fourth bar is pivotallyattached to the second end of the first bar. A ladle is removablyattached to the fourth bar, the longitudinal axis of the ladle beingsubstantially parallel to the longitudinal axis of the fourth bar. Ahydraulic cylinder or rack and pinion may be operatively associated withthe first bar to cause it to rotate about the pivotal mounting at itsfirst end. The second bar and fourth bar with the ladle attached followthe rotational motion of the first or driver bar.

12 Claims, 5 Drawing Figures MECHANICAL LADLE MECHANISM HAVING F OUR-BARCONFIGURATION BACKGROUND OF THE INVENTION 1. Field of thelnvention Theinvention relates to a four-bar mechanism having one'bar fixed, two barswhich rotate about opposite ends of the fixed bar and impart a generalplane motion to a fourth bar and a ladle attached thereto. Inparticular, the invention pertains to a four-bar mechanical ladlemechanism which lifts a ladle from a furnace in a substantially verticalposition, transports the ladle to a casting station, and causes theladle to pour the mo]- ten metal into a mold. Although the four-barmechanism is described with reference to a molten metal pouring device,the mechanism may be incorporated with a multiple of machines where itis desired to transport items from one fixed point to another fixedpoint.

2. Description of the Prior Art A number of prior art devices forconveying a molten metal from a furnace to a pouring station utilize aladle conveying mechanism which imparts a rotational motion to the ladleas it is lifted from the furnace. With these'prior art devices, as theladle is lifted from the furnace containing a molten metal, the ladle istilted or tipped due to the rotational motion imparted to it by theconveying mechanism. As the level of the molten metal in the furnacevaries due to prior extractions of the molten metal from the furnace,this tipping motion of the ladle makes it very difficult, if notimpossible, to obtain uniform shots, or amounts of molten metal in theladle between successive ladle filling events. Some prior art devicesalso utilize a four-bar mechanism, but do not restrain any of the barsfrom moving and, thus require at least two hydraulic cylinders or otherdriving means to actuate the mechanism to transport the ladle from afill position at the furnace to a pour position at a die. or moldstation.

The four-bar mechanical ladle mechanism of the present invention issimple, less expensive than the prior art mechanisms, and allows forgreater uniformity between successive'shots of molten metal in theladle.

SUMMARY OF THE INVENTION The invention provides a mechanical ladlemechanism having a four-bar frame structure having a first link or barwith a first end and a second endopposite the first end; a second linkor bar having a first end and a second end opposite its first end; athird fixed link or bar having a first end, the first endof the secondlink being pivotally attached thereto, and a second end opposite thefirst end, the first end of the first link being pivotally attachedthereto; and a fourth link having'a first end pivotally attached to thesecond end of the second link and a second end opposite the first endpivotally attached to the second end of the first link. A ladle adaptedto contain and pour molten metal is removably affixed to the fourthlink. The distance between the pivotal mounting points on the secondlink is less than the distance between the pivotal mounting points onthe first link to keep the fourth link, and ladle in a substantiallyvertical position as the first and second links pivot about theirrespective pivotal mounting points during the initial portion ofmovement of the mechanism as it lifts the ladle from a furnace whichcontains the molten metal. Driving means such as a hydraulic cylinderand clevis mounting, or rack and pinion arrangement is operativelyassociated with the first link to cause the first link to rotate aboutits point of pivotal attachment to the third fixed link. Due to thepivotal interconnection of the first, second and fourth links, thesecond and fourth links are driven by the first link and, therefore,generally follow the rotational motion of the first link.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of the preferredembodiment of the four-bar mechanical ladle mechanism.

FIG. 2 is a top view of the four-bar mechanical ladle mechanism takenalong line 2-2 in FIG. 1.

FIG. 3 is a fragmentary side view ofa portion of the mechanism shown inFIG. 1 showing the hydraulic cylinder and clevis driving means.

FIG. 4 is a fragmentary side view of a portion of the mechanism as shownin FIG. 1 showing the rank and pinion driving means.

FIG. 5 shows a side view of another embodiment of the mechanism.

DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to FIG. 1, themechanical ladle mechanisrn, generally denoted as 1, includes a firstlink or bar 3 having a first end 5 and a second end 7 opposite the firstend, and a second link 9 having a first end 11 and a second end 13opposite its first end. A third fixed link 15 has first end 17 and asecond end 19 opposite the first end 17. The first end 11 of the secondlink 9 1 is pivotally attached to the first end 17 of the third link 15,and the first end 5 of the first link 3 is pivotally attached to thesecond end 19 of the third link 15. A fourth link 21 has a first end 23pivotallyattached to the second end 13 of the second link 9 and a secondend 25 opposite the first end 23 also pivotally attached to the secondend 7 of the first link.3.

.A ladle 27, adapted to contain and pour a molten metal is removablyattached to the fourthlink 21- by attachment means 29.

With reference to FIGS. 3 and 4, driving means 31 is I operativelyaffixed to the first link 3, the first link 3 therefore constituting adriving link, and the second and fourth links being driven by the firstlink constitute driven links.

Again with reference to FIG-l, the third link l5 is fixed, i.e., haszero degrees of freedom. The first link 3 is pivotally attached near itsfirst end 5 to the third link 15 near its second end 19 for rotationalmovement about the pivotal attachment. The second link 9 is pivotallyattached near its first end 11 to the third link 15 near its first end17 for rotational movement about the pivotal attachment. The fourth link21 is pivotally attached near its first end 23 to the second link 9 nearits second end 13, and pivotally attached near its second end 25 to thefirst link 3 near its second end 25. The pivotal attachments of thefourth link 21 at its opposite ends allows the fourth link to move in ageneral plane motion, i.e., a combination of translation and rotation inthe same plane of rotation of the first link 3 and second link 9 or in aplane of rotation parallel thereto.

Attachment means 29, such as a plurality of pins 33 and notches 35, 37removably hold the ladle 27 in position adjacent the fourth link 21.

The driving means 31 may consist of any of a number of devices wellknown to those skilled in the art. With reference to FIG. 3, the drivingmeans 31 may consist of a clevis 39 affixed at one end to the first end5 of the first link 3, and a double acting hydraulic cylinder and piston41 operatively affixed to the clevis at an end thereof opposite that endaffixed to the first link 3. As the hydraulic cylinder and piston 41 areactuated to cause its associated rod to contract into the cylinder, ormove to the right as viewed in FIG. 3, the first link will be forced torotate in a counter clockwise direction about its point of pivotalattachment to the third link 15, thus causing the driven arm or secondlink 9 to also rotate in a counter clockwise direction, as viewed inFIG. 1, about its point of pivotal attachment to the third link 15, andcausing the fourth link 21 to move in a counter clockwise direction asit pivots about its points of pivotal attachment, and translate in theplane of rotation of the first link 3 and second link 9. As the rod ofthe hydraulic cylinder and piston 41 extends, the

first link 3, second link 9, and fourth link 21 are caused to rotate ina clockwise direction as viewed in FIG. 1.

With reference to FIG. 4, the driving means 31 may alternatively consistof a pinion gear 40 operatively affixed to the first end 5 of the firstlink 3, and a rack 42 operatively associated with the pinion gear 40. Asthe rack 42 translates to the right, the first link 3 is driven in acounter clockwise direction and the second link 9 and fourth link 21follow in a counter clockwise direction as they did in the embodimentdescribed above when the piston rod of the hydraulic cylinder and piston41 contracted. As the rack 42 translates to the left, the first link 3,second link 9 and fourth link 21 move in a clockwise direction as whenthe rod of the hydraulic cylinder and piston 41 extended.

Both of the embodiments, one embodying a clevis 39 and hydrauliccylinder 41, and the other using a rack 42 and pinion 40 provide asingle driving center at the pivotal attachment of the first link 3 tothethird link by which the mechanism is put into motion.

It is to be noted that in the preferred embodiment illustrated in FIG.1, the distance between the pivotal mounting points at the first andsecond ends 5, 7 of the first link 3 is greater than the distancebetween the pivotal mounting points at the first and second ends 11, 13of the second link 9, and that the pivotal mounting point of the firstlink 3 to the fourth link 21 and the pivotal mounting point of the thirdlink 9 to the fourth link 21 are on a common substantially verticalcenter-line 24.

It has been found that a relative differential of approximately one inchin the distances between the pivotal mounting points of the first link 3and pivotal mounting points of the third link 9 allows the mechanism toperform satisfactorily and results in a compact mechanism.

In the fill position, shown in solid lines in FIG. 1, a portion of theladle 27 is positioned below a top surface 43 of a molten metal bath 45in a conventional furnace 47. In this position, the ladle 27 receives ameasured amount of molten metal. It should be mentioned at this pointthat a conventional ladle of most any configuration may be employed. Asthe first link 3 rotates in a counter clockwise direction and the secondlink 9 and fourth link 21 follow in the counter clockwise movement, asviewed in FIG. 1, the centerline 24 common to the pivotal mounting ofthe first link 3 to the fourth link 21 and pivotal mounting of the thirdlink 9 to the fourth link 21 remains substantially perpendicular to thesurface 43 of the molten metal bath 45 during the first phase of itsmotion which causes the ladle 27 to exit from the molten metal bath 45in a substantially vertical position. This is due to'the geometry of themechanism 1, in particular the relationship of the distances between thepivotal mounting points of the first link 3 and the pivotal mountingpoints of the second link 9. The attribute of the mechanism 1 to liftthe ladle 27 from the molten bath 45 in a substantially verticalposition is extremely important from a practical sense in that itensures that the ladle 27 will receive a same measured amount of moltenmetal during a series of filling events, even as the surface 43 of themolten metal bath 45 varies due to the fact that previous filling eventshave depleted the amount of molten metal in the furnace 47. That is tosay, the ladle 27 is repeatedly filled with the same amount of moltenmetal in repeated filling events without the necessity of continuouslyrecharging the furnace 47 with more molten metal to maintain the surface43 at a consmnt level.

It is seen in the broken lines of FIG. 1 that as the links 3, 9 and 21rotate counter clockwise, that through the first phase of rotation thecommon centerline 24 remains substantially vertical, and the ladle 27remains substantially perpendicular to the top surface 43 of the moltenmetal bath 45. As the links 3, 9 and 21 continue to move in a counterclockwise direction, the common centerline 24 on the fourth link 21deviates substantially from the vertical and passes through thehorizontal to a point where it is at an acute angle to the horizontal.Because the ladle 27 is afi'nred to the fourth link 21, it also deviatesfrom its perpendicular position, and passes through the horizontal to apoint where it also is at an acute angle to the horizontal as the links3, 9 and 21 move counter clockwise. As the ladle 27 passes through thehorizontal it arrives at a pour position which results in molten metalcontained therein being poured into a casting means 49, such as a die ormold.

It can be seen in FIG. 1 that as the links 3 and 9 rotate to the'pourposition, the first link 3 must cross the third link 9. That is, thefirst link 3 must pass over the pivotal mounting point of the first end11 of the second link 9 to the first end 17 of the third link 15 to aposition on the opposite side of the third link 15 than that side of thethird link 15 it was on when the mechanism was in the fill position. Toaccomplish this without interference between the first link 3 and secondlink 9 or the first link 3 and the first end 17 of the third link 15,the first and second links are transversely separated or off-set fromeach other, i.e., they are in different vertical planes as can be'bestseen in FIG. 2'. The amount of off-set may be of any convenientdistance, so long as a clearance is maintained between the link 3 andlink 9, and the link 3 and first end of link 15.

In the preferred embodiment, shown best in FIG. 1, of the four-barmechanical ladle mechanism 1, the first link 3 is generally U-shaped orhas a U-shaped portion to allow the positioning of the ladle 27 deepinside a furnace holding tank by providing a clearance area below thefirst link into which a side of the furnace or holding'tank can project.In addition, this generally U- shaped first link provides a clearancebelow the first link for any accessory equipment which may be locatedadjacent the furnace or holding tank and which may, otherwise, interferewith a ladle mechanism.

In a second embodiment, illustrated in FIG. 6, the first link 3' is atan angle to the second link 9' when viewed in profile.

In the embodiment of FIG. 1, the first link 3 rotates through an angleof approximately 120 from the ladle fill position to the ladle pourposition, while the first link 3 of the embodiment of FIG. 6 rotatesthrough an angle of approximately 90 from the ladle fill position to theladle pour position.

In yet another alternative configuration, not illustrated, the four-barmechanism 1 could assume a configuration generally laterallyquadrilateral in profile when in the ladle fill. position. Moreparticularly, the first link 3 is substantially parallel to the secondlink 9, the links, of the mechanism 1 thus forming a substantiallytrapezoidal profile.

Further, in another altemative'configuration, not illustrated, the firstand second links may be bent midway between their ends both in generallythe same direction such that when viewed in aplan view the second end 7of the first bar 3 is in a different vertical plane than the first end5, and likewise, the second end 13 of the second bar 9 is in a differentvertical plane than the first end 1 1. This configuration allows agreater flexibility of mounting of the mechanical ladle mechanism,particularly in applications were there is a limited amount of space tomount the mechanism, for example,

where the space available for the mechanism is smaller than thelongitudinal lengths of the first and second bars as they areillustrated in FIG. 2.

There are a number of methods which may be employed to removably attachthe ladle 27 to the fourth link 21; the preferred way is thatillustrated in FIG. 1. In this embodiment, two generally horizontalspaced apart parallel rods or pins 33 are affixed to the fourth link 21perpendicularly to the longitudinal axis of the first link 3 and/orsecond link 9. A flange 34 is affixed to the ladle 27 to projectradially therefrom. The flange has first and second notches 35, 37,respectively, each having a rounded end opposite its open end, eachnotch being adapted to receive one of the rods 33. The first notch 35 isoriented such that its open end is toward a top edge of the flange 34,i.e., a centerline of the notch common to its rounded end and open endis perpendicular to the similar center-line of the first notch 34. Thisconfiguration holds the ladle 27 substantially parallel to the fourthlink 21, and allows the ladle to faithfullyfollow the motion of thefourth link 21. This copnfiguration also allows easy removal of theladle 27 from the fourth link 21 by rotating the ladle 27 counterclockwise, as viewed in FIG. 1, about the first notch 35 until thesecond notch 37 is free from its associated rod 33,

and then pulling the ladle in the direction of its longitudinal axisuntil the first notch 35 is free from its associated rod 33.

The foregoing detailed description is given primarily for cleamess ofunderstanding and no unnecessary limitations should be understoodtherefrom, for some modifications will be obvious to those skilled inthe art.

I claim:

1. A mechanical ladle mechanism for transporting and pouring a moltenmetal from a furnace to a casting means, comprising:

a first link having a first end and a second end opposite said firstend;

a second link having a first end and a second end posite said first end;

a third fixed link having a first end and a second end oppositesaidfirst end of said second link being pivotally attached to said firstend of said third link, and said first end of said first link beingpivotally attached to said second end of said third link;

a fourth link having a first end pivotally attached to said second endof said second link, and a second end opposite said first end pivotallyattached to said second end of said first link;

a ladle adapted to contain and pour said molten metal affixed to saidfourth link;

the distance between said first end and said second end of said firstlink being greater than the distance between said first end and saidsecond end of said second link; I

driving means operatively associated with said mechanism to cause saidfirst link and said second link to rotate about their respective pivotalmounting on said third link, and said fourth link to move in a generalplane motion in a plane of rotation similar to the plane of rotation ofsaid first link and said second link.

2. A mechanical ladle mechanism as defined in claim 1, wherein at leasta portion of said first link and at least a portion of said second linkare included in different vertical parallel planes.

3. A mechanical ladle mechanism as defined in claim 2, wherein at leasta portion of said first link is generally U-shaped to produce aclearance area.

4. A mechanical ladle mechanism as defined in claim 3, wherein saidladle is positioned on said fourth link to be generally perpendicular toa surface of said molten metal in said furnace when said mechanism is ina fill position.

5. A mechanical ladle mechanism as defined in claim 4, wherein saiddriving means is operatively associated with said first link.

6. A mechanical ladle mechanism as defined in claim 2, wherein saidfirst, second, third and fourth links form a structure generallylaterally quadrilateral in profile when said mechanism is in a fillposition.

7. A mechanical ladle mechanism as defined in claim 6, whereinsaid'ladle is positioned on said fourth link to be generallyperpendicular to a surface of said molten metal in said furnace whensaid mechanism is in a fill position.

8. A mechanical ladle mechanism as defined in claim 7, wherein saiddriving means is operatively associated with one of said first, second,third or forth links.

, 9. A mechanical ladle mechanism as defined in claim 8, wherein acommon centerline between said pivotal mounting point of said secondlink to said fourth link and said pivotal mounting point of said firstlink to said fourth link is generally perpendicular to a surface of saidmolten metal in said furnace.

10. A mechanical ladle mechanism as defined in claim 9, wherein saidgenerally laterally quadrilateral profile is substantially trapezoidal.

11. A mechanical ladle mechanism as defined in claim 10, wherein saidfirst link is generally parallel to said second link.

12. A mechanical ladle mechanism as defined in claim 11, wherein saidladle is positioned on said fourth link such that a generallylongitudinal centerline of said ladle is substantially parallel to saidcommon centerline between pivotal mounting points on said fourth link.

* k l I! l UNITED STATES IYATENT OFFICE CERTIFICATE OF CORRECTION Dated'November 27, 1973 Patent No. 3 774', 815

Inventor(s) John McCar thy It is cettified that error appesrs in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

O In the title page column I, line 5 below inventor information insert:

{73] ASSIGNEE: MPH Industries, Inc. Riverside, Mich a corporation ofMichigan Signed and sealed this 6th day oft August 197A.

' (SEAL) Attest:

MCCOY M. GIBSON, JR. C. MARSHALL DANN Commissioner of Patents AttestingOfficer

1. A mechanical ladle mechanism for transporting and pouring a moltenmetal from a furnace to a casting means, comprising: a first link havinga first end and a second end opposite said first end; a second linkhaving a first end and a second end opposite said first end; a thirdfixed link having a first end and a second end opposite said first endof said second link being pivotally attached to said first end of saidthird link, and said first end of said first link being pivotallyattached to said second end of said third link; a fourth link having afirst end pivotally attached to said second end of said second link, anda second end opposite said first end pivotally attached to said secondend of said first link; a ladle adapted to contain and pour said moltenmetal affixed to said fourth link; the distance between said first endand said second end of said first link being greater than the Distancebetween said first end and said second end of said second link; drivingmeans operatively associated with said mechanism to cause said firstlink and said second link to rotate about their respective pivotalmounting on said third link, and said fourth link to move in a generalplane motion in a plane of rotation similar to the plane of rotation ofsaid first link and said second link.
 2. A mechanical ladle mechanism asdefined in claim 1, wherein at least a portion of said first link and atleast a portion of said second link are included in different verticalparallel planes.
 3. A mechanical ladle mechanism as defined in claim 2,wherein at least a portion of said first link is generally U-shaped toproduce a clearance area.
 4. A mechanical ladle mechanism as defined inclaim 3, wherein said ladle is positioned on said fourth link to begenerally perpendicular to a surface of said molten metal in saidfurnace when said mechanism is in a fill position.
 5. A mechanical ladlemechanism as defined in claim 4, wherein said driving means isoperatively associated with said first link.
 6. A mechanical ladlemechanism as defined in claim 2, wherein said first, second, third andfourth links form a structure generally laterally quadrilateral inprofile when said mechanism is in a fill position.
 7. A mechanical ladlemechanism as defined in claim 6, wherein said ladle is positioned onsaid fourth link to be generally perpendicular to a surface of saidmolten metal in said furnace when said mechanism is in a fill position.8. A mechanical ladle mechanism as defined in claim 7, wherein saiddriving means is operatively associated with one of said first, second,third or forth links.
 9. A mechanical ladle mechanism as defined inclaim 8, wherein a common centerline between said pivotal mounting pointof said second link to said fourth link and said pivotal mounting pointof said first link to said fourth link is generally perpendicular to asurface of said molten metal in said furnace.
 10. A mechanical ladlemechanism as defined in claim 9, wherein said generally laterallyquadrilateral profile is substantially trapezoidal.
 11. A mechanicalladle mechanism as defined in claim 10, wherein said first link isgenerally parallel to said second link.
 12. A mechanical ladle mechanismas defined in claim 11, wherein said ladle is positioned on said fourthlink such that a generally longitudinal centerline of said ladle issubstantially parallel to said common centerline between pivotalmounting points on said fourth link.